Telephone-system.



No. 645,958. Patented Mar. 27, |900. A. K. KELLER.

TELEPHONE SYSTEM.

(Application led Feb. 6, 1899.)

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J NITED STATES ALBERT K. KELLER, OF PHILADELPHIA, PENNSYLVANIA, ASSIGNOR TO TI-IE INTERNATIONAL TELEPHONE AND. SWITOHBOARD COMPANY, OFPLAINFIELD, NEW JERSEY.

MANUFACTURING TELEPHONE SYSTEM.

SPECIFICATION forming part of Letters Patent No. 645,958, dated March2'7, 1900.

Application lled February 6, 1899. Serial No. 704,625. (No model.)

T all wiz/0m, it may concr'n.-

Be it known that I, ALBERT K. KELLER, a citizen of the United States,residing in the city and county of Philadelphia, State of Penn- 5sylvania, have invented certain new and useful Improvements in TelephoneSystems, of which the following is a specification, reference being hadto the accompanying drawings, forming a part hereof.

This invention relates to telephone-switchboards, and more especially tothe annunciators or drops and to the electrical connections of the samewith other parts of the system.

One object is to simplify and improve the construction of annunciatorsor drops, and a further object is to so construct the annunciators andto so arrange their electrical connections that each annunciator or dropshall serve the double purposekof a calling signal t0 indicate to theoperator the number of the subscriber who desires a connection to beestablished and as a ringing-od signal to indicate to the operator whensuch subscriber has finished his communication.

In the practical operation of the invention in the form chosen forillustration and description hereinafter the introduction of theoperators plug for the purpose of establishing desired connection afterthe operation of the calling signal is made to restore the drop to sucha position that it will respond to the ringing off by the subscriber,while the withdrawal of the plug by the operator for the purpose ofdisconnecting the subscribers lines after the ringing off again restoresthe drop to a condition in which it will serve again as a callingsignal. Moreover, the construction of the drop and the arrangement ofthe electrical connections are such that the coil of the electromagnetof the drop, which is in series in the subscribers line during thecalling, is bridged across the line by the introduction of the operatorsplug when the desired connection is established, so that the highresist- 45 ance of this coil is removed from the circuit While thetalking is going on.

The signaling device,which is employed to attract the operatorsattention, in the embodiment of the invention shown in the drawings is asmall electric lamp included in the local circuit, which is normallyopen, but is adapted to be closed .whenever the subscriber calls. It isobviously immaterial, however, what' form of signaling device isemployed.

The invention will be more fully described hereinafter with reference tothe accompanying drawings, in which- Figure l is a vertical section ofone of the annunciators or drops with partsin elevation, a portion ofthe supporting-board being indicated and the operators plug being shownin section in readiness for introduction into the jack. Figs. 2 and 3are respectively a top View and a bottom view of the annunciator or dropremoved from the board. Fig. 4 is an end view thereof with the signalingdevice and its circuit indicated diagrammatically.

In the form of the annunciator or drop representedA in `the drawings theseveral parts for convenience in manufacture are supported by a plate A,which is secured in any suitable manner to the board B. vA sleeve O isextended forward from the plate A to guide and support the operatorsplug in proper relation to parts with which it cooperates. A socket isalso provided, as at a, to receive the lamp D, which in this particularinstance is adopted as the signaling device. Upon the rear side of theplate A is secured the electromagnet E with its armor F, the lattersupporting in a suitable manner the other parts, hereinafter referredto. The armature G, pivoted at g and thrown back normally by a springg', is provided with an arm Gr', which carries a contact strip or bridgeg2, adapted to establish connection between two fixed contacts g3 'andg4 when the magnet E is energized and the armature attracted. Thearmature is retained in its forward position until released by amovement of the operators plug by a latch H, which is represented as alever pivoted at its middle and having a toe h for cooperation with theoperators plug. Two spring-contacts I and 1 arealso supported so as tocooperate, respectively, with the core and the shell or sleeve of theoperators plug. The latter is represented in Fig. 1 as of substantiallycommon construction,

having a tip or core K and a sleeve K', to which the wires of theoperators set are connected as usual.

The two spring-contacts g3 and g4 form the terminals of the localcircuit, which includes the lamp D, and is closed from one terminal tothe other by the bridge or contact-piece g2 when the armature G isattracted, whereby the lamp receives current and glows so long as thearmature is held in its forward position by the latch H. Theline-wire,(indicated at L L in Fig. 4,) which normally includes the magnetE inseries, as at Z Z', is connected on each side of the magnet, as at Z2Z3, to the contacts I I', respectively, so that when the operators plugis inserted and the talkingcircuit completed through said contacts andthe tip and sleeve of the plug and their connections the magnet becomesbridged on the line and its resistance is removed from thetalking-circuit. When the plug is inserted, a shoulder 7c on the tipengages the toe 7L of the latch II and causes the latch to release thearmature G, whereby the local circuit through the lamp is broken; butwhen the plug is thrust completely home a notch 7c receives the toe hand leaves the latch free to move again. When the subscriber hasiinished his communication and hangs up his receiver, thereby closingthe ringing-circuit through the magnet, and rings oit, the magnet isagain energized, and its armature is attracted and held by the latch H,thereby again closing the local circuit through'the lamp between thecontacts g3 g4, so that the lamp continues to glow until the latch isagain operated to release the armature by the contact of the shoulder 7cof the plug with the toe h of the latch, when the plug is withdrawn. Theremoval of the plug therefore not only breaks the local circuit throughthe lamp, but leaves the jack in its original condition in readiness torespond to another call. It will be seen, therefore, that not only isthe construction of the jack exceedingly simple, but that the singledevice, with the proper connections, serves both as a calling signal andas a ringing-od signal, thereby dispensing with a separate ringing-offsignal and the complicated connections consequent upon the use of aseparate ringing-o signal.

It will be obvious that the details of construction and arrangement maybe varied without departing from the spirit of the invention, whileproviding for the accomplishment of the same general result. Thereforethe invention is not to be limited to the precise construction andarrangement of parts shown and described herein.

I claim as my inventionl. In a telephone-annunciator, the combinationwith an electromagnet, a signaling device controlled by the armature ofsaid magnet, and line connections to said magnet, of a latch to engagesaid armature and control its movements, said latch standing in the pathof movement of the operators plug and oper ated during the insertion ofthe plug and again during the withdrawal of the plug.

2. In a telephone-annunciator, the combination with an electromagnet, alocal circuit including a signal and controlled by the armature of saidmagnet, and line connections to said magnet, of a latch to engage saidarmature and control its movements, said latch standing in the path ofmovement of the operators plug and operated during the insertion of theplug and again during the withdrawal of the plug.

3. In a telephone-annunciator, the combination with an electromagnet, anormallyopen circuit including a signal and closed by the armature ofsaid magnet when the latter is attracted, and line connections to saidmagnet, of a latch to engage said armature and retain it in its forwardposition, said latch standing in the path of movement of the operatorsplug and operated during the insertion of the plug and again during thewithdrawal of the plug to release said armature.

4. The combination with a telephone-cir cuit, a magnet included in saidcircuit, a normally-open circuit including the lamp and closed by theforward movement of the armature of said magnet, a latch to engage saidarmature and hold it in its forward position, said latch having a toe tocoperate with a shoulder on the operators plug, whereby said latch isoperated to release the armature and open said local circuit when theplug is inserted and again when the plug is withdrawn.

This specification signed and witnessed this 17th day of January, A. D.1899.

ALBERT K. KELLER.

In presence of- ANTHONY N. JESBERA, WILLIAM A. REDDING.

IOO

